docs: def create_decl_string(
              return_type, arguments_types, with_defaults=True):
          """
          Returns free function type
  
          :param return_type: function return type
          :type return_type: :class:`type_t`
          :param arguments_types: list of argument :class:`type <type_t>`
          :rtype: :class:`free_function_type_t`
  
          """
  
          return free_function_type_t.NAME_TEMPLATE % {
              'return_type': return_type.build_decl_string(with_defaults),
              'arguments': ','.join(
                  [_f(x, with_defaults) for x in arguments_types])}